The new and improved catalysts and methods of this invention involve dispersing on a finely divided and difficult to reduce inorganic oxide selected from silica, alumina, thoria, zirconia, titania, magnesia and mixtures or composites thereof an organic chromium compound or complex such as a chelate derived from an N-nitroso-substituted N-arylhydroxylamine, N-nitroso-substituted hydroxamic acid, N-aryl-substituted hydroxamic acid, or an aromatic hydroxamic acid with or without an N-substituent, and activating the resulting mixture by heating to and at an elevated temperature in a non-oxidizing atmosphere with a specific temperature range being within about 600.degree.-2000.degree. F.